1. Field of the Invention
The present invention relates generally to a steering column assembly having an energy absorption mechanism. More specifically, the present invention relates to an automotive steering column assembly having an energy absorption mechanism, which effectively absorbs impact load applied to a steering column by a driver's secondary collision when a motor vehicle accident occurs.
2. Description of the Background Art
There have been various types of safty sysmtems for the automotive steering column assembly, wherein the energy applied to the steering column by the driver's secondary collision is absorbed so as to protect the driver.
In one type of safty system, an upper steering column tube is allowed to displace relative to a lower steering column tube so as to absorb the impact load applied by the driver's secondary collision. Specifically, the upper and lower column tubes are telescopically connected at their end portions such that when the impact force applied to the upper steering column tube in the direction of the axis of the steering column is larger than a predetermined value, the upper steering column tube is allowed to move relative to the lower steering column tube, either accommodating the lower steering column tube thereinto or telescoping into the lower steering column tube.
In the prior art structure, however, since the energy absorption mechanism should be provided between the upper and lower steering column tubes and/or between upper and lower steering shafts, it is inevitably complicated in structure and difficult to provide such an energy absorption mechanism which is capable of absorbing a sufficient amount of the applied energy per se.